This invention relates to ultrasonic liquid nebulizing apparatus for atmospheric humidification and more particularly to a chamber for generating an ambient temperature aerosol within a room or the like for use in inhalation therapy.
In the treatment of respiratory diseases, techniques are employed which involve the inhalation by the patient of aerosols. Conditions accompanying many respiratory diseases are respiratory congestion and inadequate expulsion by the patient of secretions from the lungs. It has been found that a water or saline aerosol introduced into the lungs at room temperature assists in relieving and in correcting these conditions. It is conventional practice to directly introduce a medicine, such as a relaxant for treatment of asthma, into the human respiratory system in aerosol form.
Humidifiers, as they are commonly known, are of two general varieties: hot liquid vaporizers and cool vapor aerosol generators. Aerosolizers or nebulizers for cool vapor generation utilized in inhalation therapy have generally included a reusable reservoir provided with a supply of liquid and a supply of breathable gas under substantial pressure. In one type, a liquid discharge nozzle and a gas discharge nozzle are typically arranged so that a stream of the gas is discharged past the liquid to provide a mixture of gas and nebulized liquid for breathing by the patient. In another type, a whirling blade is disposed to dip intermittantly into the liquid supply thereby lifting the liquid into the path of a stream of transport gas. These conventional types of nebulizers frequently do not produce aerosol particles of uniformly small character or cause evaporation which would result in deep relaxing penetration of the aerosol into the respiratory system. Nebulizers have recently been developed which utilize ultrasonic acoustic techniques for aerosol generation. See, for example, U.S. Pat. No. 3,861,386.
A major problem associated with cold vapor respiratory therapy is the avoidance of contamination of the generated vapor by impurities carried by the recirculated ambient air. As the air recirculates through the liquid containing chamber, contaminants accumulate which can ultimately cause the transmitttal of a concentration of dangerous infectants. In the past, it has been the practice to frequently sterilize the vapor generator, especially the liquid reservoir, and then provide the liquid supply with a suitable disinfectant. Therefore, relatively frequent, expensive and somewhat cumbersome servicing of the vapor generator is required in order to maintain the requisite high standard of sanitation.